Removal & Installation - M/t GMC Cab & Chassis S15

1. Raise and support vehicle on hoist. Drain transfer case. Disconnect speedometer cable. Remove skid plate and crossmember supports as necessary. Disconnect rear drive shaft from transfer case and tie up away from work area.
2. Disconnect front drive shaft from transfer case and tie up shaft away from work area. Disconnect shift lever rod from shift rail link. Support transfer case and remove bolts attaching transfer case to transmission adapter.
3. Move transfer case to rear until input shaft clears adapter and lower assembly from vehicle.

To install, reverse removal procedure. For tightening specifications, see TORQUE SPECIFICATIONS (ALL EXCEPT "S/T" SERIES) .

1. With transfer case shift lever in "4 Hi" position, disconnect negative battery cable. Raise vehicle and remove skid plate. Drain transfer case. Mark front and rear output shaft yokes and drive shafts for reassembly reference and remove shafts.
2. Disconnect speedometer cable and vacuum harness from transfer case. Remove shift lever from case. Remove catalytic converter hanger bolts at converter. Raise transmission and transfer case assembly with jack and remove transmission mount bolts. Remove mount.
3. Lower complete assembly. Support transfer case alone and remove transmission-to-transfer case bolts. Remove shift lever bracket from transfer case adapter in order to reach upper left attaching bolt.
4. Separate transfer case from transmission adapter and remove from vehicle.

Reverse removal procedures to install. Always use a new gasket between the transfer case and adapter. For tightening specifications, see TORQUE SPECIFICATIONS ("S/T" SERIES) .

1. Place transfer case in "4H". Raise vehicle. Drain lubricant from transfer case. Remove cotter pin from shift lever swivel. Mark transfer case front and rear output shaft yokes and drive shafts for assembly alignment reference.
2. Disconnect speedometer cable and indicator switch wires. Disconnect front drive shaft at transfer case yoke. Disconnect parking brake cable guide from pivot located on right frame rail, if necessary. Remove engine strut rod from transfer case.
3. Place support under transfer case and remove transfer case-to-transmission adapter bolts. Move transfer case assembly rearward until free of transmission output shaft and remove assembly. Remove all gasket material from rear of transmission adapter housing.

To install, reverse removal procedure. For tightening specifications, see TORQUE SPECIFICATIONS (ALL EXCEPT "S/T" SERIES) .

1. On models with 117mm 4-speed, remove attaching screws from shift lever boot retainer. Slide boot assembly up shift lever and remove lever. To remove shift lever, push down on collar and turn counterclockwise.
2. On all models, raise and support vehicle under frame. Drain fluid from transmission. Disconnect speedometer cable at transmission. Remove shift controls from transmission (if not already removed). Remove parking brake lever, controls, and back-up switch wire as needed.
3. Disconnect drive shaft at transmission and position support under transmission assembly. Disconnect exhaust pipes from exhaust manifolds as needed. Remove frame crossmember and flywheel inspection plate.
4. On 117mm 4-speed, remove top 2 transmission-to-clutch housing bolts and install guide pins. On all models, remove all transmission-to-clutch housing attaching bolts, slide transmission rearward until input shaft is clear of clutch hub and remove assembly from vehicle. Remove guide pins if used.

Note. Support clutch release bearing and support assembly when removing transmission main drive gear from flywheel housing. This will prevent release bearing from falling out of flywheel housing.

Apply a light coating of high temperature grease to main drive gear bearing retainer and splined portion of transmission main drive gear shaft. Reverse removal procedures to complete installation. Refer to TORQUE SPECIFICATIONS (ALL EXCEPT "S/T" SERIES) .

1. On models with 117mm 4-speed, remove attaching screws from shift lever boot retainer. Slide boot assembly up shift lever and remove lever. To remove shift lever, push down on collar and turn counterclockwise.
2. On all models, raise and support vehicle under frame. Drain fluid from transmission and transfer case. Disconnect speedometer cable. Disconnect front and rear drive shafts at transfer case and wire out of way. Disconnect transfer case shift lever.
3. Position support under transfer case. Remove transfer case-to-adapter bolts and remove transfer case. Disconnect shift control rods from shifter levers if not already removed. Separate exhaust pipes from exhaust manifolds as needed.
4. Support rear part of engine and remove 2 adapter bolts. Remove crossmember. Remove 2 top transmission-to-clutch housing cap screws. Insert 2 guide pins (J-1126 on 117mm, J-2216 all others) in holes. Remove 2 lower transmission-to-clutch housing cap screws.
5. Slide transmission and adapter assembly rearward until clutch gear is free of splines in clutch disc. Guide pins will support transmission and prevent damage to clutch disc. Remove transmission and adapter as an assembly. Remove adapter from transmission.

Apply a light coating of high temperature grease to main drive gear bearing retainer and splined portion of transmission main drive gear shaft. Reverse removal procedures to complete installation. Refer to TORQUE SPECIFICATIONS (ALL EXCEPT "S/T" SERIES) .

ALL "S/T" SERIES

Note. If vehicle is a "T" Series (4WD model), refer to TRANSFER CASE - NP-207 ("S/T" SERIES) removal procedures and remove the transfer case.

1. Disconnect negative battery cable. On 77.5mm 4-speed, remove upper starter motor nut. On all models, remove shift lever boot screws and slide boot up shift lever. Shift transmission into neutral and remove shift lever bolts at transmission. Remove shift lever.
2. Disconnect electrical connector and clip at transmission, if present. Raise vehicle and remove drive shaft. Disconnect exhaust pipe at manifold, if needed.
3. Disconnect speedometer cable, electrical connector and clutch cable at transmission. Support transmission on jack and remove mount attaching bolts. Remove catalytic converter hanger. Remove crossmember attaching bolts and crossmember. Remove flywheel inspection cover.
4. On 77.5mm 4-speed, remove lower starter motor attaching bolt. Remove body mounting bolts on left side of body and loosen radiator support bolt. Raise cab on left side as needed to remove upper bell housing attaching bolts. Support cab with wood block between frame and cab.
5. Remove transmission-to-engine bolts on all models. Remove transmission.

Reverse removal procedures to install transmission, noting the following: On 77mm 4-speed, coat main drive gear bearing retainer and splined portion of transmission main drive gear with high temperature grease before installation. For tightening specifications, see TORQUE SPECIFICATIONS ("S/T" SERIES) .

ALL EXCEPT "S/T" SERIES

TORQUE SPECIFICATIONS (ALL EXCEPT "S/T" SERIES)

"S/T" SERIES

TORQUE SPECIFICATIONS ("S/T" SERIES)

See also:
• TORQUE SPECIFICATIONS (ALL EXCEPT "S/T" SERIES)